During the past few decades, people have been travelling over longer distances for longer periods, carrying with them larger and heavier suitcases. Lifting and manually carrying luggage at airports, railway stations, hotels or other sites is a task which is generally disliked by travelers.
Rental luggage carts are available at certain sites of this kind but the renting process is itself an inconvenience and such carts do not remain with the traveller after leaving the site of rental.
In order to mitigate this problem, wheeled luggage carriers which typically have a lightweight and foldable construction to facilitate handling and storage of the device when it is not in use, have been used. An example of such a carrier is shown in FIG. 1.
Such carriers are essentially small hand trucks of the type which have a platform on which the luggage case is rested, a pair of wheels which extend below one edge region of the platform and a handle which extends upward from the edge region. The user grasps and tilts the handle to lift the platform and luggage case upward from the underlying floor or the like and the carrier may then be pulled or pushed to the destination of the case. Such carriers are helpful but are not entirely free of inconveniences of their own.
The carrier is not self-stabilized and it is not entirely self-supporting during movement. A person who is pulling or pushing such a carrier must continually exert additional effort in order to hold the carrier at the tilted orientation that enables it to be travelled along the floor or other surface. In the absence of such effort by the user, gravity pivots the carrier until either the platform or the handle itself contacts the floor.
When the luggage case is removed from the carrier the carrier itself becomes essentially still another separate piece of luggage which the traveller must contend with.
The instability of such a carrier when it is tilted to the travelling orientation and the pivoting movement which occurs when the handle is released make it unsatisfactory for certain purposes such as for transporting a small child along with a luggage case.
Efforts have been made to make the luggage case itself wheelable without the aid of a separate carrier. This typically consists of providing wheels at the surface of the case that faces downward when the case is in an upright position.
Most case designs have wheels placed at the opposing corners of a narrow side of a conventional rectangular box-type suitcase. When in this orientation, in which the case can be wheeled along, the case is substantially higher than it is wide. An example of this type of case can be seen in FIG. 2.
The advantages of this arrangement are ease of changing between carrying and rolling the suitcase and rolling the suitcase by one's side without obstruction to walking. However the significant disadvantages are difficulty in manoeuvrability due to a long narrow base, instability due to the narrow base and a high centre of gravity and the person pulling such a case generally has to lean over into an awkward posture.
After wheels are attached to suitcases making them ‘more portable’, further innovations were aimed at optimising ergonomics, case material and case design for wheeling and manoeuvrability efficiency.
Retractable handles were built into wheeled luggage cases to facilitate movement of the case as shown in FIG. 3. When the handle is extended, the unit may be tilted about the wheels and be operated in essentially the same manner as the previously discussed luggage case carriers.
The advantages of such a design are a retractable handle, better manoeuvrability and improved ergonomics. However, such a design is meant for small and light cases. Large size suitcases that have adopted such a design have been cumbersome and tiresome to take around due to their considerable size and weight and are subject to all of the limitations of the prior carriers.
In all of the previous designs the narrow base and high centre of gravity meant that the cases were unstable.
Back in the 1980's, some tried to attach wheels to the broad side of the suitcase where the surface was widest and push (or pull) the case lying on this widest side on the wheels like a trolley (see prior U.S. Pat. No. 6,041,900 Outerrigger Inc.). This provided better stability with a wide base and low centre of gravity. However, this idea had never taken-off as there are several disadvantages inherent in the design. For example, there are practical inconveniences with potential damage to the exposed wheels during transfer/storage and in packing and unpacking with a non-stationary suitcase.
People have tried to make the wheels retractable and generally use a holding mechanism, for example a catch or latch, in order to hold the wheel in its extended position during use. An example of this is shown in U.S. Pat. No. 5,407,039 Alper, Brad and Trevethick, Richard. The multiple retractable wheels are flimsy, cumbersome and inconvenient to activate and retract. Moreover, they make the whole case too heavy for practical purposes.
In addition, the holding mechanisms are not always able to support the weight of the often heavy luggage for prolonged use which results in failure of the holding mechanism and luggage of this type will often have to be repaired or replaced on a regular basis.
There has been a long felt want for luggage which is (1) easily manoeuvrable with good stability and ergonomics and (2) convenient and practical for use. The present invention is directed to overcoming one or more of the problems discussed above.